A heat insulation material composed of a press-formed body containing silica particles or alumina particles, a radiation scattering material and reinforcing fibers is known so far (for example, Patent Document 1). A heat insulation material composed of silica particles largely shrinks when used at a temperature environment of higher than 1100° C. Therefore, a heat insulation material which has a heat resistance against at a temperature of higher than 1100° C. has been required. Further, a heat insulation material which has strength and a thermal conductivity equivalent to those of the one containing silica particles has is desired.